Read the passage below and answer questions that follow
The world's oceans cover more than 70 percent of the Earth's surface. They are home to millions of species, many of which have not yet been discovered. Oceans play a critical role in regulating the Earth's climate by absorbing heat from the sun and distributing it around the globe through ocean currents.
Marine ecosystems are under threat from human activities. Pollution, particularly plastic waste, has become a major concern. Every year, approximately eight million tonnes of plastic end up in the oceans, harming marine life and entering the food chain.
Overfishing is another serious problem. Many fish populations have declined significantly due to excessive harvesting. Scientists warn that if current fishing practices continue, some species could face extinction within decades.
Conservation efforts are underway in many countries. Marine protected areas have been established to allow ecosystems to recover. International agreements aim to reduce pollution and regulate fishing practices. However, experts agree that much more needs to be done to protect our oceans for future generations.